Radiation curable compositions based on unsaturated polyesters and compounds having at least two vinyl ether groups

Abstract

Disclosed is a liquid, radiation curable composition comprising: (A) an unsaturated polyester component containing an unsaturated polyester polymer, an unsaturated polyester oligomer or a mixture thereof; and (B) a non-polymerized, cocurable vinyl ether component which may be separate from or structurally incorporated in the unsaturated polyester component, provided that the vinyl ether component contains an average of at least two vinyl ether groups per molecule of the vinyl ether component. Also disclosed is a method of coating comprising: applying to a substrate a film of a liquid, radiation curable composition of the invention, and curing the composition through its thickness to a tack-free state by exposing the film to ionizing radiation and/or ultraviolet light.

What is claimed is: 
     
       1. A liquid, radiation curable coating composition comprising: an unsaturated polyester having a plurality of maleate and/or fumarate groups; and   a non-polymerized, cocurable vinyl ether component free radically reactive with said unsaturation of said polyester and selected from the group consisting of: (a) vinyl ether compounds containing an average of at least two reactive vinyl ether groups per molecule and (b) a vinyl ether containing group bonded to the polyester;   the composition being free of components that would destabilize the composition under coating application conditions, whereby polymerization of the vinyl ether component is substantially avoided until cocured with the unsaturated polyester when initiated by exposure to radiation.   
     
     
       2. The composition of claim 1 comprising a photoinitiator. 
     
     
       3. The composition of claim 1 wherein the ratio of carbon-carbon double bond equivalents of said vinyl ether groups to carbon-carbon double bond equivalents from said polyester is in a range of from 0.1:1.0 to 1.5:1.0. 
     
     
       4. The composition of claim 3 comprising a thermal polymerization inhibitor. 
     
     
       5. The composition of claim 3 wherein said unsaturated polyester comprises an unsaturated polyester polymer having a peak molecular weight, as measured by gel permeation chromatography using a polystyrene standard, in a range of from 800 to 50,000. 
     
     
       6. The composition of claim 5 wherein the ratio of carbon-carbon double bond equivalents of said vinyl ether groups to carbon-carbon double bond equivalents of said polyester is in a range of from 0.25:1.0 to 1.1:1.0. 
     
     
       7. The composition of claim 5 wherein said unsaturated polyester comprises an unsaturated polyester polymer having a peak molecular weight, as measured by gel permeation chromatography using a polystyrene standard, in a range of from 1,200 to 5,000. 
     
     
       8. The composition of claim 1 wherein said unsaturated polyester is an unsaturated polyester-urethane polymer, an unsaturated polyester-urethane oligomer or a mixture thereof. 
     
     
       9. The composition of claim 1 wherein the composition consists essentially of the unsaturated polyester and the vinyl ether component, and optionally a photoinitiator and/or a thermal polymerization inhibitor. 
     
     
       10. The composition of claim 1 wherein the polyester component comprises the reaction product of a polyhydric alcohol with an unsaturated carboxylic acid selected from the group consisting of maleic acid, fumaric acid, and itaconic acid. 
     
     
       11. The composition of claim 10 wherein the backbone of the unsaturated polyester includes a plurality of unsaturated ester groups selected from the group consisting of maleate, fumarate, and itaconate. 
     
     
       12. The composition of claim 1 wherein the unsaturated polyester contains a plurality of fumarate groups. 
     
     
       13. The composition of claim 1 wherein the vinyl ether component includes a reaction product of a di-, tri-, or tetra-functional organic polyol and acetylene. 
     
     
       14. The composition of claim 1 wherein the vinyl ether component includes a member selected from the group consisting of: tripropylene glycol divinyl ether, diethylene glycol divinyl ether, 1,4,-butanediol divinyl ether, and tetraethylene glycol divinyl ether. 
     
     
       15. A substrate having thereon a cured film comprising the crosslinked product of the unsaturated polyester containing and vinyl ether containing coating composition of claim 1. 
     
     
       16. The coated article of claim 15 wherein the polyester component comprises the reaction product of a polyhydric alcohol with an unsaturated carboxylic acid selected from the group consisting of maleic acid, fumaric acid, and itaconic acid. 
     
     
       17. The coated article of claim 16 wherein the backbone of the unsaturated polyester includes a plurality of unsaturated ester groups selected from the group consisting of maleate, fumarate, and itaconate. 
     
     
       18. The substrate of claim 15 wherein the unsaturated polyester contains a plurality of fumarate groups. 
     
     
       19. The coated article of claim 15 wherein the vinyl ether component includes a reaction product of a di-, tri-, or tetra-functional organic polyol and acetylene. 
     
     
       20. The coated article of claim 15 wherein the vinyl ether component includes a member selected from the group consisting of: tripropylene glycol divinyl ether, diethylene glycol divinyl ether, 1,4,-butanediol divinyl ether, and tetraethylene glycol divinyl ether. 
     
     
       21. A method of coating comprising: (A) applying to a substrate a film of a liquid, radiation curable composition containing an unsaturated polyester having a plurality of maleate and/or fumarate groups and a non-polymerized, cocurable vinyl ether component free radically reactive with said unsaturation of said polyester and selected from the group consisting of: (a) vinyl ether compounds containing an average of at least two reactive vinyl ether groups per molecule and (b) a vinyl ether containing group bonded to the polyester, the composition being free of components that would destabilize the composition under coating application conditions, whereby polymerization of the vinyl ether component is substantially avoided until cocured with the unsaturated polyester when initiated by exposure to radiation; and   (B) curing said composition through its thickness to a tack-free state by means of crosslinking the polyester component using the vinyl ether groups as the primary crosslinking agent, the curing being effected by exposing said film to ionizing radiation and/or ultraviolet light.   
     
     
       22. The method of claim 21 wherein the ratio of carbon-carbon double bond equivalents of said vinyl ether groups to carbon-carbon double bond equivalents from said polyester is in a range of from 0.1:1.0 to 1.5:1.0. 
     
     
       23. The method of claim 22 wherein said composition contains a photoinitiator. 
     
     
       24. The method of claim 22 wherein said composition contains a thermal polymerization inhibitor. 
     
     
       25. The method of claim 22 wherein said unsaturated polyester comprises an unsaturated polyester polymer having a peak molecular weight, as measured by gel permeation chromatography using a polystyrene standard, in a range of from 800 to 50,000. 
     
     
       26. The method of claim 25 wherein the ratio of carbon-carbon double bond equivalents of said vinyl ether groups to carbon-carbon double bond equivalents of said polyester is in a range of from 0.25:1.0 to 1.1:1.0. 
     
     
       27. The method of claim 25 wherein said unsaturated polyester comprises an unsaturated polyester polymer having a peak molecular weight, as measured by gel permeation chromatography using a polystyrene standard, in a range of from 1,200 to 5,000. 
     
     
       28. The method of claim 21 wherein said unsaturated polyester is an unsaturated polyester-urethane polymer, an unsaturated polyester-urethane oligomer or a mixture thereof. 
     
     
       29. The method of claim 21 wherein said unsaturated polyester is present in the radiation curable composition as a separate compound from said vinyl ether component. 
     
     
       30. The method of claim 21 wherein the composition applied to the substrate consists essentially of the unsaturated polyester and the vinyl ether component, and optionally a photoinitiator and/or a thermal polymerization inhibitor. 
     
     
       31. The method of claim 30 wherein the backbone of the unsaturated polyester in the composition applied to the substrate includes a plurality of unsaturated ester groups selected from the group consisting of maleate, fumarate, and itaconate. 
     
     
       32. The method of claim 21 wherein the unsaturated polyester contains a plurality of fumarate groups. 
     
     
       33. The method of claim 21 wherein the vinyl ether component of the composition applied to the substrate includes a reaction product of a di-, tri-, or tetra-functional organic polyol and acetylene. 
     
     
       34. The method of claim 21 wherein the vinyl ether component of the composition applied to the substrate includes a member selected from the group consisting of: tripropylene glycol divinyl ether, diethylene glycol divinyl ether, 1,4,-butanediol divinyl ether, and tetraethylene glycol divinyl ether.